Flagellin, but not CpG ODN, promotes development of IL-4-producing CD4 T cells in the draining LN.

Abstract

<p>4get/KN2 reporter mice were administered OVA, OVA plus flagellin (1 μg), or OVA plus CpG (0.75 μg) i.n. on d0, 1 and 2. In addition, to block IL-12 action in some mice, mice were given anti-IL-12 p40 or control antibody (rat IgG2a) twice, one day before initial sensitization (700 μg i.p.) and again on d2 (300 μg i.p.). On d6, expression of IL-4 reporters (GFP⁺hCD2⁺) by CD4 T cells was examined in the mediastinal LN. (<b>A</b>) Gating strategy of CD4 T cells (CD4⁺), activated CD4 T cells (CD4⁺CD44^hiB220^-CD62L^-), and T_FH cells (CD4⁺CD44^hiB220^-CD62L^-PD-1⁺CXCR5⁺). (<b>B</b>) Numbers of CD4 T cells, percentages and numbers of GFP⁺IL-4⁺(hCD2⁺) CD4 T cells. (<b>C</b>) Percentages and numbers of activated CD4 T cells, percentages and numbers of T_FH cells, and percentages and numbers of GFP⁺IL-4⁺(hCD2⁺) T_FH. Data are pooled from two independent experiments with combined totals of 8 mice per group. Each circle represents one individual mouse. Error bars indicate mean +SD. * P ≤ 0.05, ** P ≤ 0.01, *** P ≤ 0.001 using one-way anova with Bonferroni post-test.</p